Apparatuses for drawing crystals usually include a framework or support structure of metal pipes or metal sections, to which the assemblies required for the drawing process, e.g., the vacuum chamber, the transfer lock, the lock chamber, and the drawing element, are attached.
Thus, an apparatus for zonal melting without a crucible is known (DE 1,290,117), which consists of a two vertical guide columns, which are mounted on a pedestal and which are connected at the top by a transverse strut. The columns carry two arms with the rod holders; the arms can be moved relative to each other and relative to a stationary heating device. The arms are coupled to a differential gear, and the two guide columns are equipped with support elements, which are attached at the top by means of screw threads to the transverse strut and at the bottom to the pedestal, and which extend at an angle to the guide columns and also to each other. The guide columns are connected to the pedestal by means of flectors of equal height in the form of slots open on the side facing the support elements.
This known device is not suitable for apparatuses for drawing very large crystals, because the individual assemblies of such a large device are too bulky and too heavy for installation in the known support structure, and they are also too difficult of access for the service personnel.
Finally, an older application (DE 195 38 857.7) proposes an apparatus for drawing single crystals from a melt in a crucible under vacuum or under a protective gas at reduced pressure, in which the crucible, which can be heated by the thermal radiation from a heating element, is mounted on a crucible support bolt in a vacuum chamber supported on a stand. A drawing element is provided above the melt, by means of which the crystal can be drawn from the surface of the melt in the upward direction into a transfer lock chamber, which can be pivoted laterally with respect to the base stand. A separation device is also provided between the crystal and the drawing element, which makes it possible to separate the crystal from the drawing element. The base stand consists of a platform supported by posts. Additional legs are supported at three of the four corners of the approximately rectangular platform, which holds the vacuum chamber. The three vertical legs are of equal length and are held together at the their top ends by a horizontal frame, which forms a right triangle. The area projected by this frame onto the platform circumscribes approximately half of the area of the platform. A gallows or pivot arm, to which the lock chamber is attached, is supported on at least one of the legs. The pivot arm is parallel to the legs and extends approximately as far as the cover of the vacuum chamber.
The task of the present invention is to create a device of the type described above, by means of which the cover of the vacuum chamber, which is located between the lock chamber and the crucible for melting the silicon, and which seals off the crucible off from above, can be lifted from the vacuum chamber, then pivoted, and finally rotated for the purpose of cleaning. The device is intended to be inexpensive to produce, to require a minimum of space, and to be adjustable in the sense that the cover can be moved by the device into a precisely defined end position.
This task is accomplished in accordance with the present invention by a sleeve, which surrounds the bolt and which can be rotated on it; by projections, which are permanently attached to the sleeve and which extend outward horizontally from it; by a bolt which is held by the projections and which extends transversely to them; and by a housing component in the form of a sleeve, which can pivot around the bolt, where a threaded spindle with a hand lever is mounted in the housing, the spindle being parallel to, and a certain distance away from, the sleeve component of the housing, the spindle cooperating with a nut, which is mounted on the sleeve, and where the sleeve component surrounds a journal, which is rigidly connected to the device part to be lifted or to the cover.
Additional details and features are described herein, and the scope of the invention set forth in the claims.